Pitchometer attachment



Jun 10, 1947. w E. LITTLE ETAL v PITCHOMETER ATTACHMENT.

Filed Sept. 14, 1945 INVENTOR LIT Tr; E BY M 5. McrKlws TRY Wztmm E. W

ILLLA ATTORNEY Patented June 10, 1947 PITCHOMETER ATTACHMENT William E. Little and William S. McKinstry, Richmond, Calif.

Application September 14, 1945, Serial No. 616,432

(Granted under the act of March 3, 1883, as

1 Claim.

This invention relates to a gauging device and more particularly to a pitchometer rod attachment.

In the manufacture of propellers and the shaping of other objects having surfaces of compound curvature, the machining and grinding required. to reduce rough castings and blanks to proper thickness and curvature requires frequent accurate measuring. A measuring device known as a pitchometer is commonly employed.

Pitchometers employ a pitchometer rod as their measuring means.

'Each pitchometer rod is mounted so as to traverse the area of an object being gauged in an erect position, always remaining parallel to its original position. The pitchometer rod is vertically slidable to gauge thickness and curvature. Such a gauging means is accurate where the surface being worked is in a plane approximately at right angles to the longitudinal axis of the pitchometer rod. As the curvature deviates from such a plane, the accuracy of the gauging decreases When the curvature is such that the pitchometer rod can only engage the surface at or near a tangential position, great inaccuracy results.

The problem is further complicated by the fact that conventional plans for such objects give the cutaway and over raise measurements at right angles to the pitch.

Objects of our invention are, therefore, to provide a pitchometer rod attachment facilitating the accurate gauging of curvature and thickness; to provide an improved device for adjustably positioning a gauging means in relation to a selected portion of a curved surface being'measured, and to provide improved elements and arrangements thereof in a support of the character and for the purposes set forth.

In accomplishing these and other objects of the present invention, we have provided irriproved details of structure, the preferred form of which is illustrated in the accompanying drawing wherein:

Fig, 1 is a front elevation of the pitchometer rod attachment embodying the features of the present invention.

Fig. 2 is a side elevation of the pitchometer rod attachment as viewed from the left of the pitchometer rod attachment as seen in Fig. 1.

Referring more in detail to the drawing:

In Fig. 1 and Fig. 2, the numeral l indicates a pitchometer rod commonly employed to gauge thickness and curvature of surfaces.

amended April 30, 1928; 370 0. G. 757) 2 In Fig. 1, 2 indicates an object to be worked having a curved surface.

The pitchometer rod attachment embodying this invention preferably consists of a clamping collar 3 slidably fitted to the pitchometer rod I. The collar 3 is preferably cut at 4 to permit constriction and expansion of the collar.

On each side of the cut 4 outwardly extended flanges 5 and 6 are provided. An opening 1 is provided in the flange 6 and a screw threaded opening 8 juxtaposed thereto in the flange 5.

A screw threaded bolt 9 is inserted through the opening 1 and engaged in the opening 8. The

bolt 9 has a shoulder 50 formed thereon to bear against the flange 6 to draw flanges 5 and 6 together as the bolt is tightened. For convenience in rotating the bolt, a knurled head H is provided.

On a portion of the collar 3, clear of the flanges 5 and 6 and the bolt 9, a mounting face I2 is provided having a screw threaded opening l3 formed therein as shown in Fig. 2.

A substantially rectangular elongated arm member l4, having an opening l5 formed therein for mounting purposes is shown in both figures.

An arm mounting bolt having a screw threaded portion I6, a bearing portion IT, a shoulder l8 and a knurled head l9 are indicated in Fig. 2. The mounting bolt is inserted through the open ing I5 of the arm member [4, the screw threaded portion I6 engaged in the opening l3, and the entire arm member pivoted on the bearing portion I! of the mounting bolt. To hold the arm inadjusted position the bolt 16 is tightened. The shoulder I8 is forced against the arm It to maintain it in place against the mounting face l2.

. The arm member M' has two parallel transverse ridges 2|] and 2| formed in its extended end portion, The ridges 20 and 2| with the arm member l4 comprise a channel substantially at right angles to the longitudinal axis of the arm member.

An opening 22 is formed through the arm memher in the bottom arm portion of the channel as shown in Fig. 2.

A substantially rectangular gauge rod holder 23 having an angular extension 24 formed thereon is slidably engaged between the ridges 2i! and 2|. The holder 23 has an elongated mounting opening 25 formed longitudinally therein. A bolt 26 is passed through the elongated opening 25 and the opening 22 in the arm member. A knurled nut 2! is provided for the bolt 26. Mounted in this way, the rod holder may be adjustably positioned in the channel formed by transverse ridges 20 and 2! on the channel. formed 3 arm member I4 and secured in adjusted position by tightening the nut 21.

A gauge rod substantially cylindrical in shape and marked off in a graduated scale along its longitudinal axis is shown at 28. Conducive to accuracy in measuring, a sharpened point 29 is formed at its lower end.

To mount the gauge rod 28 in the holder 23, an opening 30 is formed in the angular extension 24 of said holder in a position to slidably support the gauge rod in a position substantially parallel to the holder 23 and at right angles to the axis of the arm member I4.

To assist in the reading of the graduations on the gauge rod, a substantially conical indicator 3I having a cylindrical opening coaxially formed therein, is mounted on the angular extension 24 circumjacent the gauge rod 28. The upper edge of the indicator 3|, being in a plane at right angles to the longitudinal axis of the gauge rod 28, is a useful means for reading the graduated scale from every direction from which the gauge is visible.

A protractor plate 32 is secured on the mounting face I2 in spaced relation to the arm member I4 to measure angles of adjustment between the pitchometer rod I and the said arm member I4.

Operation The operation of the pitchometer rod attachment constructed as described is as follows:

The collar 3 of the pitchometer rod attachment is slipped over the pitchometer rod I. The attachment is elevated to the desired position as measured on the pitchometer rod and is secured in place by tightening the bolt 9. So mounted the pitchometer rod attachment traverses the object 2 being gauged as the pitchometer rod is moved.

The arm member I4 is pivotally adjusted until the gauge rod 28 is perpendicular to the surface of the object 2 being worked. This is done by setting the arm member I4 at an angle with the pitchometer rod equal to the angle formed by the axis of the pitchometer rod,- generally the vertical, and the surface of the object 2. This angle is customarily available on plans for the object 2.

.At this stage, the sharpened point 29 of the gauge rod 28 is rested on a point of the object 2 to be used as a reference point. The reading at the top of the indicator 3| is carefully noted.

An area to be compared with the reference point the amount of the cutaway or over raise required.

It is sometimes found preferable to readjust the elevation of the attachment on the pitchometer rod when a reference point has been determined in order to have the gauge rod I4 indicate any selected starting graduation.

While we have shown but one embodiment of our invention, it is susceptible to modification without departing from the spirit of the invention. We do not wish, therefore, to be limited by the disclosures set forth, but only by the scope of the appended claim.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

We claim:

.A pitchometer rod attachment comprising a split clamping collar slidably fitted circumjacent a pitchometer rod, means engaging opposite portions of the split clamping collar to maintain the collar in adjusted position on the pitchometer rod, an arm member pivotally mounted on the collar to pivot in a plane parallel to the longitudinal axis of the pitchometer rod and having a transverse channel formed in its outer end portion, a protractor plate supported on the clamping collar to measure angles between the pitchometer rod and the arm member, a gauge rod holder having an elongated longitudinal opening formed therein slidably mounted in the transverse channel of the arm member having an angular extension with an opening provided therein, an adjustment bolt positioned within the elongated opening of the holder and engaging the arm member to permit. the securing of the slidably mounted holder in adjusted position, a graduated rod slidably supported in the opening in the angular extension of the holder substantially parallel to the holder and at right angles to the longitudinal axis of the arm member, and indicating means mounted in spaced relation to the graduated rod.

WILLIAM E. LITTLE. WILLIAM S. MCKINSTRY.

REFERENCES CITED The f ll win references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,095,059 Donnelly Oct. 5, 1937 2,172,368 Eby Sept. 12, 1939 1,696,525 Coolidge Dec. 25, 1928 1,547,380 Godfrey July 28, 1925 

